In order to enable high-speed communication and accommodate a large amount of communication traffic, next generation communication systems employ a multi-hop relay scheme. The multi-hop relay scheme is a scheme for transferring data in the form of a multi-hop by using fixed or mobile relay stations (RS), and a communication system employing the multi-hop relay scheme (hereinafter referred to as “multi-hop communication system”) can quickly reconfigure a network in response to a change in surrounding environments and thus can more efficiently operate the whole wireless network.
Also, the multi-hop communication system can extend service coverage and increase system capacity through a multi-hop. That is, when channel conditions between a base station (BS) and a mobile station (MS) are poor, the BS can provide the MS with a wireless channel with better conditions by configuring a multi-hop relay path by using RSs.
Meanwhile, in next generation communication systems, research has been actively conducted to provide a scheduling method for efficiently using limited resources. In order to efficiently use limited resources, not only unnecessary resource allocation must be prevented, but also already allocated resources must be quickly recovered and reallocated for other services. In addition, for efficient use of resources in data transmission/reception, fast bandwidth allocation must be made in response to a bandwidth allocation request for data transmission. A polling scheme is one of exemplary bandwidth allocation schemes.
The polling scheme is a scheme in which a BS allocates a bandwidth to an RS at regular periodic intervals. That is, since an RS is allocated a bandwidth from a BS at regular periodic intervals, it can transmit data without separately taking steps with the BS, that is, without requesting the BS to allocate a bandwidth and being allocated a bandwidth, when receiving the data from an MS.
However, the polling scheme has a problem with allocating a bandwidth at regular periodic intervals. That is, since the interval between bandwidth allocation periods is regular, resources for polling may be saved whereas a time delay lengthens when a bandwidth period is long, and a time delay may decrease whereas polling resources are wasted when a bandwidth allocation period is short. Thus, there is a problem in that it is difficult to efficiently use resources.
Therefore, in submitting a request for resource allocation and allocating a resource in response to the request, there is a need for a way to effectively allocate a bandwidth by changing a bandwidth allocation period at regular intervals according to system situations.